Learn Portuguese (Portugal): O voo custa duzentos e trinta euros. - The flight costs two hundred and thirty euros.

In Portuguese, numbers in the hundreds (from 200 to 900) change their ending to match the gender of what you are counting. Because euros is a masculine word, we use the masculine form duzentos. If we were counting a feminine word, like moedas (coins), it would be duzentas moedas.

Why does voo have two O's?

Voo is the noun for flight. The double vowel means you stretch the O sound out slightly when speaking. You might sometimes see it spelled with a little hat accent (vôo) in older texts, but that accent was removed in a recent spelling reform.

Do I always have to use e (and) when saying large numbers like 230?

Yes! In Portuguese, you must use e between the hundreds and the tens. So 230 is always duzentos e trinta, never just duzentos trinta. You also use it between tens and units, for example, 35 is trinta e cinco.

Which verb does custa come from?

It comes from the regular verb custar (to cost). Since o voo (the flight) is a singular thing, we use the form for he, she, or it. We drop the -ar from the end of the dictionary form and add -a, giving us custa.